Not sure if this has been brought up.
But I have been watching Secrets of the Force and TFA back to back and after lots of observation. I believe some parts of the suits used in the film are made of rubber and plastic.
There's lots of squeaking when the armour was put on during this scene from Secrets of the Force. And look at the contour on the chest and torso..
And the amount of flex during this scene on Finn's armor.
Would this be a requirement for a future centurio